Much of this course revolved around the isomorphism conjecture
that Hartmanis felt at the time could lead to a proof that P ≠
NP.

On 2/18/85 Hartmanis stated that whether there is an oracle where PH
is infinite is an open question and
on 3/13/85 Hartmanis announced that Yao found such an oracle but no
mention of how Yao's proof worked, i.e., no circuit complexity.